Question: Evaluate the definite integral. $\int^2_{1}3x^{-2}\,dx = $
Answer: First, use the power rule: $\int^2_{1}3x^{-2}\,dx ~=~-3x^{-1}\Bigg|^2_{1}$ Second, plug in the limits of integration: $[-3\cdot2^{-1}]-[-3\cdot1^{-1}] = -1.5+3 = 1.5$. The answer: $\int^2_{1}3x^{-2}\,dx = 1.5$